In LTE dual connectivity, the UE can receive or transmit data from or to multiple evolved NodeB (eNBs). There is a Master eNB (MeNB) and one or more Secondary eNBs (SeNB). In LTE release 12 specifications, only the case of one MeNB and one SeNB is considered.
Dual Connectivity in a LTE network can significantly improve per-user throughput and mobility robustness by allowing UEs to be connected simultaneously to a master cell group (MCG) and a secondary cell group (SCG) via a MeNB and a SeNB, respectively. The increase in per-user throughput is achieved by aggregating radio resources from at least two eNBs. The dual connectivity helps also in load balancing between MCG and SCG.